There are numerous technical applications for piezoelectric actuators, such as a piezoelectric actuator for controlling the position of valve needles of injectors in fuel injection systems. The base bodies of conventional piezoelectric actuators are formed by a piezoceramic, which expands due to the piezoelectric effect when an electrical voltage or a charge is applied.
One problem in using piezoceramics previously was that piezoceramics have a certain sensitivity to temperature fluctuations. In practice, frequent temperature changes at piezoelectric actuators influence their effectiveness in such a way that the actuator lift is reduced over time. When the piezoelectric actuator is used in injectors, a reduction of the actuator lift results in a displacement of the opening and closing timing of the valve needle and thus ultimately in a faulty injection quantity.
German Patent Application No. DE 10 2004 018 211 A1 describes a piezoelectric actuator which activates a valve element of a fuel injection device. It is checked whether the request exists for starting the internal combustion engine, and a polarization of the piezoelectric actuator is requested if the result of the check is positive.